Prediction of High-Intensity Pulverized Coal Combustion

Abstract

The overall characteristics of high-intensity pulverized coal combustion have been predicted by a one-dimensional model. The mixing of the primary stream of pulverized coal and transport air with secondary combustion air was estimated by a growth angle of the primary jet. The coal particle burnout was strongly affected by the extent of devolatilization, which varies among coals. The extent of devolatilization as characterized by variation in a devolatilization coefficient was correlated with either proximate volatiles percentage or H/C mass ratio of the virgin coal. The resulting comparisons or predictions with measurements for eight coal types and three different combustors show that observed trends are generally predicted. The data used for these comparisons were obtained from a wide range of high-intensity combustion experiments. The proximate volatile matter in the virgin test coals ranged from 16 to 40 percent while the coal feed rate was varied from 12 to 290 kg/hr. Combustion air temperature varied from 297 to 1483 K while residence time ranged from 3 to 140 ms. Comparative results suggest that the predictive method can be useful in interpreting high intensity combustion test results.